M Rashvand - Department of surface coatings and corrosion, Institute for color science and technology, No. ۵۵, Vafamanesh St., Hossein abaad Sq., Pasdaran Crossing, Tehran, Iran.
Z Ranjbar - Department of surface coatings and corrosion, Institute for color science and technology, No. ۵۵, Vafamanesh St., Hossein abaad Sq., Pasdaran Crossing, Tehran, Iran

Effect of nano TiO2 particles (P25 from Degussa Co.) on the UV protection and also corrosion properties of the coatings based on the aromatic polyurethane was investigated. Coatings were applied on standard phosphated steel panels by cathodically electrodeposition process and also nano TiO2 particles can codeposit on the cathode surface during cathodic electrodeposition. For survey on weathering resistance of the coatings, the coated panels were exposed to UV radiation in QUV chamber for 1080 hours (45days) according to ASTM G53 standard. It was found that in presence of nano titania particles, photodegradation reactions of the aromatic polyurethane network delayed for a longer time also it was found that deep cracks are formed in the films in which no nano titania is present.

polyurethane coatings; nano titania; electrochemical impedance spectroscopy (EIS); cathodic electrodeposited films; corrosion